Change in non-small-cell lung cancer tumor size in patients treated with nintedanib plus docetaxel: analyses from the Phase III LUME-Lung 1 study.

BACKGROUND: Nintedanib in combination with docetaxel is approved in the European Union and other countries for the treatment of patients with advanced non-small-cell lung cancer (NSCLC) of adenocarcinoma histology after first-line chemotherapy, based on the overall survival findings of Phase III LUME-Lung 1 study. Change in target lesion size over time as a treatment effect was assessed in patients from this study. METHODS: Tumor size was evaluated using predefined tumor measurements. Mixed-effects models were used to quantify individual relationships between time from randomization and tumor burden, measured as the sum of longest diameter (SLD) of target lesions and assessed by an independent review (Response Evaluation Criteria In Solid Tumors [RECIST] v1.0). Exploratory analyses were conducted on the overall adenocarcinoma population, adenocarcinoma patients with time from start of first-line therapy <9 months (TSFLT <9), adenocarcinoma patients who had progressive disease as best response to first-line therapy (PD-FLT), and in squamous cell carcinoma patients. RESULTS: Estimated mean baseline SLD was 82.5 mm in the adenocarcinoma (n=658), 88.3 mm in the TSFLT <9 (n=405), 98.1 mm in the PD-FLT (n=117), and 94.3 mm in the squamous cell carcinoma (n=555) populations. Treatment with nintedanib/docetaxel showed a significant reduction in tumor size over time (P<0.0001) in patients with adenocarcinoma compared with placebo/docetaxel, and in patients with squamous cell carcinoma (P=0.0049). Treatment difference at 6 months was 9.7 mm in the overall adenocarcinoma population, 16.8 mm in the TSFLT <9 population, 19.7 mm in the PD-FLT population, and 6.8 mm in the squamous cell carcinoma population. SLD at 2 months post-randomization was identified as a surrogate endpoint for overall survival, in addition to progression-free survival, for all except the PD-FLT population. CONCLUSION: Treatment with nintedanib/docetaxel significantly decreased tumor burden and decelerated tumor size over time compared with placebo/docetaxel in the overall adenocar-cinoma population, including in patients with the poorest prognosis due to aggressive tumor dynamics.

Time since start of first-line therapy as a predictive clinical marker for nintedanib in patients with previously treated non-small cell lung cancer.

INTRODUCTION: No predictive clinical or genetic markers have been identified or validated for antiangiogenic agents in lung cancer. We aimed to identify a predictive clinical marker of benefit for nintedanib, an angiokinase inhibitor, using data from two large second-line non-small cell lung cancer Phase III trials (LUME-Lung 1 ([LL1] and LUME-Lung 2). METHODS: Predictive marker identification was conducted in a multi-step process using data from both trials; a hypothesis was generated, confirmed and validated. Statistical analyses included a stepwise selection approach, a recursive partitioning method and the evaluation of HRs, including treatment-by-covariate interactions. The marker was finally validated using a prospectively defined hierarchical testing procedure and treatment-by-covariate interaction for overall survival (OS) based on LL1. RESULTS: Time since start of first-line therapy (TSFLT) was identified as the only predictive clinical marker. A cut-off of 9 months was chosen for further analysis, based on HRs and recursive partitioning. The prospectively defined final validation using OS data from LL1 established the strong relationship between TSFLT and treatment with nintedanib. Patients with adenocarcinoma with TSFLT <9 months showed a greater survival benefit (median OS 10.9 vs 7.9 months, HR 0.75 [95% CI 0.60-0.92]; p=0.0073) compared with patients in the TSFLT >9 months group (median OS 17.0 vs 15.1 months, HR 0.89 [95% CI 0.66-1.19]). CONCLUSIONS: Patients with shorter TSFLT derive a greater progression-free survival and OS benefit from nintedanib. This clinical marker could be used for patient selection and further investigation is warranted regarding pathways promoting aggressive tumour growth and antiangiogenic tyrosine kinase inhibitor benefit.

Embracing model-based designs for dose-finding trials.

BACKGROUND: Dose-finding trials are essential to drug development as they establish recommended doses for later-phase testing. We aim to motivate wider use of model-based designs for dose finding, such as the continual reassessment method (CRM). METHODS: We carried out a literature review of dose-finding designs and conducted a survey to identify perceived barriers to their implementation. RESULTS: We describe the benefits of model-based designs (flexibility, superior operating characteristics, extended scope), their current uptake, and existing resources. The most prominent barriers to implementation of a model-based design were lack of suitable training, chief investigators' preference for algorithm-based designs (e.g., 3+3), and limited resources for study design before funding. We use a real-world example to illustrate how these barriers can be overcome. CONCLUSIONS: There is overwhelming evidence for the benefits of CRM. Many leading pharmaceutical companies routinely implement model-based designs. Our analysis identified barriers for academic statisticians and clinical academics in mirroring the progress industry has made in trial design. Unified support from funders, regulators, and journal editors could result in more accurate doses for later-phase testing, and increase the efficiency and success of clinical drug development. We give recommendations for increasing the uptake of model-based designs for dose-finding trials in academia.

Comprehensive Biomarker Analyses in Patients with Advanced or Metastatic Non-Small Cell Lung Cancer Prospectively Treated with the Polo-Like Kinase 1 Inhibitor BI2536.

BACKGROUND: Polo like kinase 1 (PLK1) is frequently upregulated in tumors and is thus viewed as a promising therapeutic target in various cancers. Several PLK1 inhibitors have recently been developed and clinically tested in solid cancers, albeit with limited success. So far, no predictive biomarkers for PLK1 inhibitors have been established. To this end, we conducted a post-hoc biomarker analysis of tumor samples from non-small cell lung cancer (NSCLC) patients treated with the PLK1 inhibitor BI2536 in a phase II study. METHODS: We analyzed formalin-fixed paraffin-embedded surplus tumor tissue from 47 study patients using immunohistochemistry (IHC) and DNA sequencing of KRAS, EGFR, BRAF, and PIK3CA. RESULTS: KRAS-mutated patients showed numerically prolonged progression-free survival, but statistical significance was not established. Interestingly, when pathways rather than single genes were analyzed, a positive correlation between IHC staining of activated ERK (p-ERK) and mutated KRAS was detected, whereas KRAS mutation status was found to be negatively correlated with activated AKT (p-AKT). CONCLUSION: With this hypothesis-generating study in BI2531-treated patients, we could not establish a correlation between KRAS mutations and relevant clinical endpoints. Future clinical trials with concomitant systematic biosampling and comprehensive molecular analyses are required to identify biomarkers predictive for response to PLK1 inhibitors.

Nintedanib plus pemetrexed versus placebo plus pemetrexed in patients with relapsed or refractory, advanced non-small cell lung cancer (LUME-Lung 2): A randomized, double-blind, phase III trial.

OBJECTIVES: LUME-Lung 2 investigated the efficacy/safety of nintedanib plus pemetrexed in patients with pretreated non-squamous non-small cell lung cancer (NSCLC). MATERIALS AND METHODS: Patients with stage IIIB/IV or recurrent non-squamous NSCLC who had received one prior chemotherapy regimen were randomized (1:1 stratified by histology [adenocarcinoma/non-adenocarcinoma], prior bevacizumab, Eastern Cooperative Oncology Group performance status and presence of brain metastases) to receive intravenous pemetrexed 500mg/m2 on Day 1 plus nintedanib 200mg orally twice daily or matching placebo on Days 2-21, every 3 weeks until progression/unacceptable toxicity. Progression-free survival (PFS) by independent central review was the primary endpoint. Overall survival (OS) was the key secondary endpoint. RESULTS: Based on the pre-planned futility analysis of investigator-assessed PFS, conducted by an independent data monitoring committee, recruitment was halted on 18 June 2011 after 713 (n=353 nintedanib/pemetrexed; n=360 placebo/pemetrexed)/1300 planned patients had enrolled. There were no safety concerns. Subsequent analysis demonstrated a significant improvement in PFS favoring nintedanib/pemetrexed over placebo/pemetrexed (median 4.4 months vs 3.6 months; hazard ratio [HR]=0.83, 95% confidence interval [CI] 0.70-0.99, p=0.0435). There was no significant difference in OS (median 12.0 months vs 12.7 months; HR=1.01, 95% CI 0.85-1.21, p=0.8940) after 514 deaths. Nintedanib/pemetrexed resulted in a higher incidence of grade ≥3 elevated alanine aminotransferase (23.3% vs 7.3%), elevated aspartate aminotransferase (12.1% vs 1.7%) and diarrhea (3.5% vs 1.1%) compared with placebo/pemetrexed, but no difference in hypertension, bleeding or thrombosis. CONCLUSION: Although recruitment stopped prematurely, combining nintedanib with pemetrexed significantly prolonged PFS in patients with advanced non-squamous NSCLC after first-line chemotherapy, with a manageable safety profile.

Analysis of patient-reported outcomes from the LUME-Lung 1 trial: a randomised, double-blind, placebo-controlled, Phase III study of second-line nintedanib in patients with advanced non-small cell lung cancer.

INTRODUCTION: The LUME-Lung 1 trial (NCT00805194; Study 1199.13) demonstrated a significant overall survival (OS) advantage for nintedanib plus docetaxel compared with placebo plus docetaxel as second-line therapy for patients with advanced non-small cell lung cancer (NSCLC) and adenocarcinoma histology. Patient-reported outcomes (PROs) for symptoms and health-related quality of life (QoL) are reported here. METHODS: PROs were assessed at screening, on Day 1 of each 21-day treatment cycle, at the end of active treatment, and at the first follow-up visit. PRO instruments were the European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire C30 and Lung Cancer-13 supplement, and the EuroQol disease-generic questionnaire (EQ-5D and EQ-VAS). Analyses of PRO items for lung cancer-specific symptoms of cough, dyspnoea and pain were prespecified. RESULTS: Rates of questionnaire completion were high. There was no significant difference in time to deterioration of global health status/QoL, or symptoms of cough, dyspnoea or pain, between the treatment groups for both the overall study population and the adenocarcinoma population. Time to deterioration of some gastrointestinal events was shorter with nintedanib versus placebo. Longitudinal analysis for the adenocarcinoma population showed comparable changes between the groups in symptom scores over time, with numerical differences in favour of nintedanib for cough and pain scales, and significant reductions in some pain items with nintedanib versus placebo. There was no statistically significant difference in EQ-5D or EQ-VAS between the groups. CONCLUSION: The significant OS benefit observed with the addition of nintedanib to docetaxel therapy was achieved with no detrimental effect on patient self-reported QoL.

Docetaxel plus nintedanib versus docetaxel plus placebo in patients with previously treated non-small-cell lung cancer (LUME-Lung 1): a phase 3, double-blind, randomised controlled trial.

BACKGROUND: The phase 3 LUME-Lung 1 study assessed the efficacy and safety of docetaxel plus nintedanib as second-line therapy for non-small-cell lung cancer (NSCLC). METHODS: Patients from 211 centres in 27 countries with stage IIIB/IV recurrent NSCLC progressing after first-line chemotherapy, stratified by ECOG performance status, previous bevacizumab treatment, histology, and presence of brain metastases, were allocated (by computer-generated sequence through an interactive third-party system, in 1:1 ratio), to receive docetaxel 75 mg/m(2) by intravenous infusion on day 1 plus either nintedanib 200 mg orally twice daily or matching placebo on days 2-21, every 3 weeks until unacceptable adverse events or disease progression. Investigators and patients were masked to assignment. The primary endpoint was progression-free survival (PFS) by independent central review, analysed by intention to treat after 714 events in all patients. The key secondary endpoint was overall survival, analysed by intention to treat after 1121 events had occurred, in a prespecified stepwise order: first in patients with adenocarcinoma who progressed within 9 months after start of first-line therapy, then in all patients with adenocarcinoma, then in all patients. This trial is registered with ClinicalTrials.gov, number NCT00805194. FINDINGS: Between Dec 23, 2008, and Feb 9, 2011, 655 patients were randomly assigned to receive docetaxel plus nintedanib and 659 to receive docetaxel plus placebo. The primary analysis was done after a median follow-up of 7·1 months (IQR 3·8-11·0). PFS was significantly improved in the docetaxel plus nintedanib group compared with the docetaxel plus placebo group (median 3·4 months [95% CI 2·9-3·9] vs 2·7 months [2·6-2·8]; hazard ratio [HR] 0·79 [95% CI 0·68-0·92], p=0·0019). After a median follow-up of 31·7 months (IQR 27·8-36·1), overall survival was significantly improved for patients with adenocarcinoma histology who progressed within 9 months after start of first-line treatment in the docetaxel plus nintedanib group (206 patients) compared with those in the docetaxel plus placebo group (199 patients; median 10·9 months [95% CI 8·5-12·6] vs 7·9 months [6·7-9·1]; HR 0·75 [95% CI 0·60-0·92], p=0·0073). Similar results were noted for all patients with adenocarcinoma histology (322 patients in the docetaxel plus nintedanib group and 336 in the docetaxel plus placebo group; median overall survival 12·6 months [95% CI 10·6-15·1] vs 10·3 months [95% CI 8·6-12·2]; HR 0·83 [95% CI 0·70-0·99], p=0·0359), but not in the total study population (median 10·1 months [95% CI 8·8-11·2] vs 9·1 months [8·4-10·4]; HR 0·94, 95% CI 0·83-1·05, p=0·2720). Grade 3 or worse adverse events that were more common in the docetaxel plus nintedanib group than in the docetaxel plus placebo group were diarrhoea (43 [6·6%] of 652 vs 17 [2·6%] of 655), reversible increases in alanine aminotransferase (51 [7·8%] vs six [0·9%]), and reversible increases in aspartate aminotransferase (22 [3·4%] vs three [0·5%]). 35 patients in the docetaxel plus nintedanib group and 25 in the docetaxel plus placebo group died of adverse events possibly unrelated to disease progression; the most common of these events were sepsis (five with docetaxel plus nintedanib vs one with docetaxel plus placebo), pneumonia (two vs seven), respiratory failure (four vs none), and pulmonary embolism (none vs three). INTERPRETATION: Nintedanib in combination with docetaxel is an effective second-line option for patients with advanced NSCLC previously treated with one line of platinum-based therapy, especially for patients with adenocarcinoma. FUNDING: Boehringer Ingelheim.

A phase I open-label dose-escalation study of intravenous BI 2536 together with pemetrexed in previously treated patients with non-small-cell lung cancer.

INTRODUCTION: BI 2536 is a potent, highly selective inhibitor of polo-like kinase (Plk) 1. This open-label, phase I study investigated the maximum tolerated dose (MTD), safety, efficacy, and pharmacokinetics (PK) of BI 2536 IV in combination with standard-dose pemetrexed in previously treated advanced or metastatic non-small-cell lung cancer. PATIENTS AND METHODS: A standard 3 + 3 design was used. The patients received 500 mg/m(2) pemetrexed and escalating doses of BI 2536 on day 1 every 3 weeks. The primary objective was the MTD of BI 2536 combined with pemetrexed. Secondary endpoints were response rate (Response Evaluation Criteria in Solid Tumors), overall safety, and PK. RESULTS: Forty-one patients received BI 2536 (100-325 mg). Two dose-limiting toxicities (DLT) occurred at BI 2536 325 mg (grade 3 pruritus and rash; grade 4 neutropenia). Therefore, the MTD for BI 2536 in combination with pemetrexed was 300 mg. After expanding the MTD dose level, 3 additional patients experienced DLTs, which resulted in expansion of the 250 mg cohort, in which 4 of the 13 additional patients experienced DLTs. Therefore, the recommended dose of BI 2536 was 200 mg. Most frequently reported drug-related adverse events were fatigue (71%), nausea (37%), and rash (34%). Two patients had durable confirmed partial responses; 21 (54%) patients had stable disease after the treatment cycle 2. PK analysis showed that BI 2536 and pemetrexed exposure were not altered when coadministered. CONCLUSION: BI 2536 200 mg combined with standard-dose pemetrexed has an acceptable safety profile in relapsed non-small-cell lung cancer. The antitumor activity observed is encouraging and supports further investigation of Plk inhibitors.

How is retrospective independent review influenced by investigator-introduced informative censoring: a quantitative approach.

A reliable determination of progression is of key importance in determining progression-free survival in oncology trials. An independent review of tumour assessments made by investigators is often implemented with the aim of reducing a possible bias. Often, the independent review is performed in a prespecified but retrospective fashion by reviewing a patient after all assessments have been performed. It has been discussed that this mechanism can lead to informative censoring with respect to independent review. This is caused by the fact that often no further assessments are available after the investigator has declared the patient to be progressive, possibly leading to a considerable amount of patients being judged progressive by the investigator and being censored by independent review. We introduce and investigate a model for the error in assessment with the aim of quantifying the bias in independent review. The model is based on single error probabilities at each assessment time-point that are independent from each other but dependent on the time to the true progression time-point. The bias introduced for the independent review is described and quantified. We show that the investigator assessments of progression can lead to less bias for progression-free survival than the results for independent review. Results show that a within-arm discordance rate is not necessarily correlated with the bias in independent review. Finally, we propose an approach for a sensitivity analysis that is a useful tool to sandwich the true underlying distribution by the results for independent review itself and the described sensitivity analysis.

Anomalous Auditory Cortex Activations in Colored Hearing Synaesthetes: An fMRI-Study.

Color percept induction in synaesthetes by hearing words was previously shown to involve activation of visual and specifically color processing cortex areas. While this provides a rationale for the origin of the anomalous color percept the question of mechanism of this crossmodal activation remains unclear. We pursued this question with fMRI in color hearing synaesthetes by exposing subjects to words and tones. Brain activations in word condition accompanied by highly reliable color percepts were compared with activations in tone condition with only occasional color percepts and both contrasted to activations in normal subjects under the same stimulus conditions. This revealed that already the tone condition similar to the word condition caused abnormally high activations in various cortical areas even though synaesthetic percepts were more rare. Such tone activations were significantly larger than in normal subjects in visual areas of the right occipital lobe, the fusiform gyrus, and the left middle temporal gyrus and in auditory areas of the left superior temporal gyrus. These auditory areas showed strong word and tone activation alike and not the typically lower tone than word activation in normal subjects. Taken together these results are interpreted in favour of the disinhibited feedback hypothesis as the neurophysiological basis of genuine synaesthesia.

The efficacy and safety of BI 2536, a novel Plk-1 inhibitor, in patients with stage IIIB/IV non-small cell lung cancer who had relapsed after, or failed, chemotherapy: results from an open-label, randomized phase II clinical trial.

OBJECTIVE: To investigate the efficacy, safety, and pharmacokinetics of two dosing schedules of BI 2536, a novel polo-like kinase-1 inhibitor, in patients with relapsed stage IIIB/IV non-small cell lung cancer. METHODS: Ninety-five patients were randomized to intravenous BI 2536 on day 1 (200 mg) or days 1 to 3 (50 or 60 mg) of a 21-day treatment course. BI 2536 doses were escalated beyond course 2 if well tolerated. The primary objective was response, and the secondary objectives were progression-free survival (PFS) and overall survival (OS), quality of life, safety, and pharmacokinetics. Primary statistical aim was to demonstrate the difference in objective response rate to historical placebo for both treatment groups. RESULTS: Four patients (4.2%) had a partial response; two were confirmed by independent review. Median PFS was 8.3 weeks (58 days 95% confidence interval [CI]: 48-85) and 7 weeks (49 days 95% CI: 46-70) assessed by investigator and independent review, respectively. Median OS was 28.7 weeks (201 days 95% CI: 180-305). No statistically significant difference was observed between the two treatment schedules regarding clinical benefit, PFS, or OS. Grade 4 neutropenia occurred in 37% of patients; common nonhematologic adverse events were fatigue (31%) and nausea (27%). Two deaths (pulmonary hemorrhage and sepsis) were considered drug related. There was a trend in favor of the days 1 to 3 dosing schedule in quality of life. BI 2536 displayed moderate interpatient variability. CONCLUSIONS: BI 2536 monotherapy has modest efficacy and favorable safety in relapsed non-small cell lung cancer. The findings support the further development of polo-like kinase-1 inhibitors within this indication.

Phase I study of the angiogenesis inhibitor BIBF 1120 in patients with advanced solid tumors.

PURPOSE: BIBF 1120 is an oral, potent angiokinase inhibitor targeting receptors of the vascular endothelial growth factors, platelet-derived growth factors, and fibroblast growth factors. This phase I, accelerated titration study assessed the maximum tolerated dose, safety, pharmacokinetics, and pharmacodynamic effects of BIBF 1120. PATIENTS AND METHODS: Sixty-one patients with advanced cancers received BIBF 1120 in successive cohorts. Twenty-five received 50 to 450 mg once daily and 36 received 150 to 300 mg twice daily in 4-week treatment courses interspersed by 1 week of washout. Dynamic contrast-enhanced magnetic resonance imaging assessed antiangiogenic effect in 42 patients. RESULTS: Most frequent BIBF 1120-related adverse events were mostly mild to moderate (Common Toxicity Criteria grade 1-2) nausea (68.9%), vomiting (45.9%), and diarrhea (44.3%). The majority of dose-limiting adverse events of Common Toxicity Criteria grade 3 or 4 were reversible liver enzyme elevations. The maximum tolerated dose was 250 mg of BIBF 1120 for once and twice daily dosing. BIBF 1120 was absorbed moderately fast (t(max) = 1-3 hours at steady state), with no deviation from dose linearity and no decrease of exposure over time. The gMean terminal half-life was from 13 to 19 hours. One complete and two partial responses occurred in patients with renal cell cancer (n = 2) and colorectal cancer (n = 1). Dynamic contrast-enhanced magnetic resonance imaging showed a significant reduction in tumor blood flow in 55% of evaluable patients. CONCLUSIONS: BIBF 1120 dosed continuously displayed a favorable safety and pharmacokinetics profile, and first efficacy signals were observed. Twice daily dosing permitted increased drug exposure without additional toxicity. Two hundred milligrams BIBF 1120 twice daily is the recommended dose for phase II monotherapy studies.

An open-label dose-escalation study of BIBF 1120 in patients with relapsed or refractory multiple myeloma.

BACKGROUND: To determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of BIBF 1120, a triple angiokinase inhibitor administered once-daily in patients with advanced multiple myeloma. PATIENTS AND METHODS: This Phase I study included 17 patients. Planned dose escalations of BIBF 1120 were 100, 200, 250 and 300 mg. Safety and pharmacokinetic (PK) assessments were performed. RESULTS: Two DLTs (200 and 250 mg) occurred due to increased gamma-glutamyltransferase levels (CTC grade 3). The 250 mg dose was well tolerated; no dose escalation beyond 250 mg was made. The most common adverse events included diarrhoea, nausea and vomiting. No detectable deviation from dose linear PKs was observed. Regarding tumour control, two patients had stable disease for > or = 4 months. CONCLUSION: BIBF 1120 was safe and well tolerated up to 250 mg/day. The MTD was not reached.

A statistical model for the dependence between progression-free survival and overall survival.

Among the surrogate endpoints for overall survival (OS) in oncology trials, progression-free survival (PFS) is more and more taking the leading role. Although there have been some empirical investigations on the dependence structure between OS and PFS (in particular between the median OS and the median PFS), statistical models are almost non-existing. This paper aims at filling this gap by introducing an easy-to-handle model based on exponential time-to-event distributions that describe the dependence structure between OS and PFS. Based on this model, explicit formulae for individual correlations are derived together with a lower bound for the correlation of OS and PFS, which is given by the fraction of the two medians for OS and PFS. Two methods on how to estimate the parameter of the model from real data are discussed. One method is based on a maximum-likelihood estimator whereas the other method uses a plug-in approach. Three examples from non-small cell lung cancer are considered. In the first example, the parameters of the model are determined and the estimated survival curce is compared with the observed one. The second example explains how to obtain sample size estimates for OS based on assumptions on median PFS and OS. Finally, the third example provides a way of modelling and quantifying confounding effects that might explain a levelling of differences in OS although a difference in PFS is observed.

Working memory specific activity in auditory cortex: potential correlates of sequential processing and maintenance.

Working memory (WM) tasks involve several interrelated processes during which past information must be transiently maintained, recalled, and compared with test items according to previously instructed rules. It is not clear whether the rule-specific comparisons of perceptual with memorized items are only performed in previously identified frontal and parietal WM areas or whether these areas orchestrate such comparisons by feedback to sensory cortex. We tested the latter hypothesis by focusing on auditory cortex (AC) areas with low-noise functional magnetic resonance imaging in a 2-back WM task involving frequency-modulated (FM) tones. The control condition was a 0-back task on the same stimuli. Analysis of the group data identified an area on right planum temporale equally activated by both tasks and an area on the left planum temporale specifically involved in the 2-back task. A region of interest analysis in each individual revealed that activation on the left planum temporale in the 2-back task positively correlated with the task performance of the subjects. This strongly suggests a prominent role of the AC in 2-back WM tasks. In conjunction with previous findings on FM processing, the left lateralized effect presumably reflects the complex sequential processing demand of the 2-back matching to sample task.

Auditory stream segregation relying on timbre involves left auditory cortex.

An important aspect of auditory scene analysis is sequential grouping of sounds that are similar to one another in preference to sounds that follow one another. This grouping problem is captured by stream segregation tasks with alternating distinct sounds. We examined human auditory cortex activity with low noise fMRI in a stream segregation experiment relying on timbre differences of alternating harmonic tones (organ-like and trumpet-like). We found that stream segregation performance in comparison to monitoring a non-separable control stream increased activation exclusively in left auditory cortex and particularly in posterior areas. Our results suggest that left auditory cortex is selectively involved in this complex sequential task although the available cue for sequential grouping was timbre, usually attributed to right hemisphere analysis.